Upon comparing the skull of the Valparaiso variety with
that of a
British specimen of Mus decumanus, I could perceive no
difference. A skull from West Falkland did not differ, neither did the
dentition of the Keeling Island specimen above noticed. A perfect
specimen of this last I have not had an opportunity of examining.

2. MUS (DECUMANUS var. ?) MAURUS.

Mus maurus, Waterh. in Proceedings of the
Zoological
Society of London, for February, 1837, p. 20.

DESCRIPTION. — The character of the fur of this animal
nearly
resembles that of Mus decumanus; it is, however, of a
harsher
nature: the general colour of the upper parts and sides of the body is
purple-black, arising from the longest hairs being of this colour, and
likewise the tips of those which are next in length; the latter,
however, excepting at the tip, are white, and this white is not
entirely hidden, even when the hairs are in their ordinary position :
on the head the hairs assume a brownish hue, and are tolerably uniform
: the limbs, and under parts of the body, are of a deep gray colour,
with a faint purple-brown wash: the under fur is gray: the ears are
small, of a brown-white, or very pale brown colour, and furnished with
minute brown hairs: the small, scattered, bristly hairs of the tail
are of an uniform brownish-black colour. The hairs of the moustaches
are black at the base, and grayish at the apex.

This rat is very closely allied to Mus decumanus,
and I
think may possibly prove an extraordinary local variety of that animal.
Having but one skin, and no skull, I am unable to satisfy myself on
this point. Its size, as will be seen by the admeasurements, exceeds
that of the common rat, or, rather, it exceeds ordinary specimens of
that animal, for I have seen some which were equal to it.

"It was killed near Maldonado, where it frequented holes
in the
sand hillocks near the shore. It is likewise found on the island of
Guritti. If ships are ever infested with these monstrous rats, the
above-mentioned localities are very likely places to have received
colonies by such means. An old male weighed fifteen ounces and three
quarters. The ears of this rat, when alive, were of a pale colour,
which made a singular contrast with the black fur of its body."—D.

3. MUS JACOBIÆ.

Mus decumanoïdes,* Waterh. in "Catalogue of
the Mammalia
preserved in the Museum of the Zoological Society of London."

DESCRIPTION. — The general tint of the upper parts of this
rat, is
grayish-brown, (very nearly resembling that of Mus decumanus)
; the
longest hairs, which on the hinder portion of the back are one inch and
a half in length, are black; the ordinary hairs are black at the apex,
there is then, on each hair, a considerable space occupied by pale
yellow, and the remaining, or basal portion, is grayish white; the
under fur is gray: the hairs of the chin, throat, and under parts of
the body, are white, and without any gray colour at the roots: the
feet are covered with dirty grayish hairs: the tail, which is slender,
is very sparingly furnished with minute black hairs, both above and
beneath: the ears are of moderate size, of a brownish flesh colour,
and, to the naked eye, appear to be destitute of hair. The hairs of the
moustaches are most of them black at the base, and grayish at the apex.

* The MS. name of M. decumanoïdes,
which I
had applied to
this animal, has been changed, in consequence of my having seen a
different species, with the same name attached, in the museum of the
India House.

This species is scarcely equal in size to a full grown
common black
rat, (Mus Rattus), the head is rather shorter in proportion,
the tarsi are smaller, and the tail is longer. In the character of the
fur, and length of the hairs, it very closely resembles that
species: the ears are larger than in M. decumanus, and
about
equal to those of M. Rattus. In having the hairs of the
under
parts of the body of an uniform colour, (i. e. not gray at the base,)
it resembles the Mus Tectorum of Savi; but the large size
of that animal, the greater length of the fur, and its colouring, all
serve to distinguish it from the present species, which I may here
observe, is truly an old world form, and very distinct from another
species, also from the Galapagos, which is hereafter described.

"It is very common in James Island, but is not found on
all the
islands, if on any other in the Archipelago. Although its appearance is
so like that of the common rat, yet its habits appear to be rather
different: it is less carnivorous, and does not appear to be so
strongly attached to the habitations of man. This island was
frequented, about one hundred and fifty years since, by the vessels
belonging to the Bucaniers; so that the common rat might easily have
been transported here. And if a very peculiar climate, a volcanic soil,
and strange food, can together produce a race, or strongly marked
variety, there is every probability of such change having taken place
in this case."—D.

DESCRIPTION.—No. 1. The general colour of this animal is
what might
be termed black, there is, however, an obscure purple-brown hue on the
upper parts of the body, and the sides and under parts have a grayish
tint, the hairs covering the feet above are of an uniform deep
purple-brown, almost black. All the hairs of the body are gray at the
base: the hairs of the moustaches are long and numerous, and of a
black colour, having one or two white hairs intermixed: the ears are
of moderate size, and very sparingly furnished with

minute dark hairs: the tail is long and slender, and has
small,
scattered, bristly hairs, of a brown-black colour.

In.

Lines.

In.

Lines.

Length

from nose to root of tail . .

7

0

Length

of ear . . . . .

0

7

of
tail . . . . . .

6

6

from
nose to ear . . . .

1

6

of tarsus . . . . . .

1

3½

No. 2. Hairs along the centre of the back chiefly black,
and but
obscurely annulated, near the apex, with deep yellow: towards the
sides of the body, and over the haunches, the hairs are more distinctly
annulated, and on the sides of the body they are of a pale yellow at
the apex: on the under parts the hairs are gray, tipped with dirty
yellowish white: the feet are of the same deep purple-brown hue as in
the specimen first described.

Habitat, Ascension Island, Atlantic Ocean, (July.)

These two animals not only differ in the colour of the
fur, one
being of a grizzled brownish colour, and the other black, but there is
a considerable difference in the texture of the fur. In the black
specimen, the fur is very soft and glossy, and the long hairs, which
are abundant, are very slender. In the brown specimen, the fur is of a
harsher nature, the long hairs are not so abundant, but longer, and
less slender. On the other hand, they agree in size, dentition, the
length of the head, tarsus, and ears, and differ but in a trifling
degree (about three lines,) in the length of the tail.

Upon comparing the Ascension Island specimens with M.
Rattus,
I
find that, although in size they are about one third less, yet the
teeth precisely agree, not only in form, but in size. The relative
proportions of the head, ears, and tarsi, also agree. Besides the
general colouring of the fur, they both differ in having the hairs of
the feet uniformly purple-black, those in Mus Rattus being
much paler, and even whitish, on the toes. In the character of the fur,
there is much difference. The long silky hairs, which are so
conspicuous in Mus Rattus, are replaced, in the black
specimen, by hairs which are scarcely to be distinguished from the
ordinary fur; and in the other specimen, although rather longer and
more distinct, they are short, compared with those of the black rat.

" The specimen which has a black, and glossy fur,
frequents the
short coarse grass near the summit of the island, where the common
mouse likewise occurs. It is often seen running about by day, and was
found in numbers, when the island was first colonized by the English, a
few years since. The other, and browner coloured variety, lives in the
out-houses near the sea-beach, and feeds

chiefly on the offal of the turtles, slaughtered for the
daily food
of the inhabitants. If the settlement were destroyed, I feel no doubt
that this latter variety would be compelled to migrate from the coast.
Did it originally descend from the summit ? and, in the case just
supposed, would it retreat there ? and, if so, would its black colour
return ? It must, however, be observed, that the two localities are
separated from each other by a space, some miles in width, of bare lava
and ashes. Does the summit of Ascension, an island so immensely remote
from any continent, and the summit itself surrounded by a broad fringe
of desert volcanic soil, possess a small quadruped, peculiar to itself
? Or, more probably, has this new species been brought, by some ship,
from some unknown quarter of the world ? Or, I am again tempted to ask,
as I did in the case of the Galapagos rat, has the common English
species been changed, by its new habitation, into a strongly marked
variety ?"— D.

Mr. Darwin seems to have foreseen the difficult problem
which these
two rats have furnished, and although I have spent much time in
studying the Muridæ, I must confess I have been exceedingly puzzled by
the animals in question. It appears as if the brown, and black rats, (M.
decumanus, and M. Rattus,) and likewise the common
mouse, (M. Musculus,)* all of which follow man in his
peregrinations, and which, to a certain degree, are dependent upon man,
and may therefore be termed semi-domestic animals; like really domestic
animals, are subject to a greater degree of variation than those
species which hold themselves aloof from him.

Upon the whole then I have determined to describe the two
Ascension
Island specimens as one species, and as varieties of the Mus
Rattus, but with a mark of doubt, since I do not possess
sufficient materials for a rigorous examination, having, in fact, but
one skin of each variety, and neither skull nor skeleton. I have also
applied the name of insularis, to designate this variety or
species, whichever it may be, for, supposing it be not a distinct
species, it is so marked a variety, that a name for it is desirable.

* The great Bandicoot rat of India, (Mus
giganteus,
of
Hardwicke,) ought, perhaps, to be added to the species above enumerated
; and I strongly suspect several catalogued species will prove but
varieties of this animal.

Of this species, there are six specimens in Mr. Darwin's
collection
; two were found "living in the short grass, near the summit of the
Island of Ascension, where the climate is temperate."— D. Two others
were procured "on a small, stony, and arid island, near Porto Praya,
the capital of St. Jago, in the Cape de Verde Islands,—climate very hot
and dry. Excepting during the rainy season, which is of short duration,
these little animals can never taste fresh water, nor does the island
afford any succulent plant."—D. A specimen was also procured "on a
grassy cliff, on East Falkland Island, at the distance of a mile from
any habitation. It is singular that so delicate an animal should be
able to subsist under the cold, and extremely humid climate, of the
Falkland Islands, and on its unproductive soil."—D. These specimens are
all of them rather less than full grown individuals of the same species
procured in England; in other respects, they do not differ.

The sixth specimen, which is from Maldonado, is
considerably less
than British specimens of the common mouse, and is of a richer and
brighter colour, the head is smaller, the muzzle shorter in proportion,
whilst the tarsi are even longer than in a large specimen of M.
Musculus. These points of dissimilarity induced me to believe it
was a distinct species, and to apply to it the specific name of brevirostris.*
Upon re-examination, with the advantage of more experience, and
consequently a better knowledge of the characters of these animals, I
have changed my opinion. The teeth indicate that it is not an adult
specimen, and agree perfectly with those of M. Musculus, both
in form and size. "Common in the houses of the town of Maldonado, and
its habits are similar to those of Mus Musculus." — D.

* See Proceedings of the Zoological Society
for
February 14th,
1837, p. 19.

DESCRIPTION.—Fur long and soft; general colour pale
yellow-brown,
the
hairs of the ordinary fur being fulvous near the apex, and the longer
hairs brown. On the sides of the body, cheeks, and external side of
limbs, the fulvous hue prevails. The inner side of the limbs and the
under parts of the body are white, but have an indistinct yellowish
hue. All the hairs of the body are of a deep gray colour at the base.
The ears are small, well clothed with hairs; those on the inner side
are chiefly yellow; externally, on the fore part they are brown, and
posteriorly whitish. The feet are of a flesh-colour, and furnished
above with white hairs; the tarsi are but sparingly provided with
minute hairs on the upper side, and are naked beneath: they are of
unusually large size. The fore feet are of moderate * size, and
furnished with a very large carpal tubercle. The tail is very nearly
double the length of the body, if the latter be measured in a straight
line; it is of a brownish flesh-colour above, paler beneath, and
sparingly furnished with minute bristly hairs; those on the upper
surface being brown, and on the under side white. The hairs of the
moustaches are long, of a black colour, and grayish at the apex.

In.

Lines.

In.

Lines.

Length

from nose to root of tail . .

3

9

Length

of tarsus (claws included) . .

1

1

of
tail . . . . .

5

3

of
ear . . . . .

0

4

from nose to ear . . .

0

10½

Habitat, Chile.

* As I shall have occasion to use the
terms moderate,
long,
short, large, &c. it may be well to state that I take the
common mouse, (Mus Musculus,) as my standard of comparison.
The ears, feet, tail, length of the fur, general proportions, &c.
are in that animal what I term moderate.

The most conspicuous characters of the present species
consist in
the immense length of the tail, and the great size of the hinder feet.
* It is about equal in size to Mus Musculus; its form,
however, is somewhat stouter; in colour it is much paler and brighter.
The head is larger in proportion; the ears are smaller, and more
densely clothed with hair; the fore feet are rather larger, and the
fleshy tubercle on the under side of the wrist is also larger. The
thumb nail is flattened, and rounded at the tip, as in Mus
Musculus, but is longer, and more distinct than in that animal.

The skull of M. longicaudatus, (Plate 34, Fig.
1,) is
considerably larger than that of the common mouse, but in form scarcely
differs from it; its upper surface is rather more convex, and the
interparietal bone proportionately less. The length of the skull is 1
inch; breadth, 6½ lines; distance between the fore part of the
incisor, and the first molar of the upper jaw, 3½ lines. The dentition
is figured in Plate 34, Figs. 1. b and 1. c.

The above account is drawn up from the same specimen as
that from
which Mr. Bennett took his description, and which was brought from
Chile by Mr. Cuming, who states that the animal in question lives in
trees, and constructs its nest with grass.

In Mr. Darwin's collection, I find an animal which agrees
in all the
more important characters with the one above described, but differs in
being of a deeper colour, (approaching more nearly, in this respect, to
the common mouse,) and in having the tail a trifle shorter. The skull
is about ¾ of a line shorter, but its proportions agree precisely: the
proportions of the feet, and the general form of the animal, also
agree. This specimen is likewise from Chile, (Lat 37° 40',) and,
according to Mr. Darwin, "overran the wooded country south of
Concepcion, in swarms of infinite numbers. Captain FitzRoy, on his
return from visiting the wreck of H. M. S. Challenger, had the kindness
to bring me this specimen. So destructive was this little animal, that
it even gnawed through the paper of the cartridges belonging to the
people who were wrecked."—D.

* A long tarsus is generally accompanied by
a
proportionately long
tail. I presume that those Mice which have long tarsi are in the habit
of making great leaps, and that in these leaps, the tail serves to
steady and balance the body.

DESCRIPTION.—Fur very long and soft; general colour of
the upper
parts of the body pale brownish yellow; the lower portion of the
cheeks, and the under parts of the body pure white: the hairs of the
ordinary fur of the back are gray at the base, pale ochre near the
apex, and brown at the apex; the longer hairs are brownish. On the
sides of the body where the longer hairs are less numerous, the pale
ochre colour prevails; the hairs on this part as on the back are deep
gray at the base, but at a short distance from the apex they are white
; nearer the tip shaded into yellow, and at the tip brownish: the
limbs externally are of a pale yellow colour. The hairs of the throat
and chest are pure white to the root, those on the belly are obscurely
tinted with gray at the root. The feet are of a pale flesh-colour, and
furnished with white hairs; the fore feet are of moderate size; the
thumb nail is small and rounded, and the carpal tubercle is covered
with hairs; the tarsi are long, and the white hairs extend over the
whole of the under parts; the under side of the toes, however, are but
sparingly furnished. There appears to be but one large tubercle on the
under side of the tarsus, and this, which is situated near the base of
the toes, is thickly covered with silvery-white hairs. The tail is
long, pale brown above, and pale flesh-colour beneath; above, it is
furnished with minute brown hairs, and on the under side with white
hairs. The ears are rather large, of a pale flesh colour, tolerably
well clothed with hairs, which are of a pale yellow colour on the inner
side, and white on the outer side — excepting on the fore part, where
they are brown. A small tuft of white hairs springs from the base of
the ear posteriorly. The hairs of the moustaches are moderate; black
at the base, and grayish at the apex.

Upon comparing the skull (Pl. 34, fig. 2, a.) of M.
elegans with that of M. Musculus, the most evident
points
of distinction consist in the greater proportionate length of the nasal
and frontal bones, and the slenderness of the zygomatic arch in the
former animal. Length of skull 11 lines, width 6 lines, distance
between front molar and outer side of incisors of upper jaw 33/8 lines,
length of nasal bones 43/8 lines.

The dentition is figured in Pl. 34, figs. 2. b,
and 2. c.

" Whilst bivouacking one night on shore, amongst some sand
hillocks, this mouse, with its tail singed, leapt out of a bush which
was placed on the fire. Its hind legs appeared long in proportion to
the front, and it did not appear to be very active in endeavouring to
make its escape."—D.

Mus elegans is about equal in size to M.
Musculus; the
head is larger in proportion than in the latter, the ears are slightly
larger, the tail is longer, and so are the tarsi. The large ears, long
tail, and comparatively large size of the feet, combined with the
greater size of the animal itself, will render it easy to distinguish
this species from M. gracilipes and M. bimaculatus. From
the last mentioned animal it moreover differs in having the head larger
in proportion, the fur longer, and the colouring of the upper parts of
the body somewhat darker. The white fur is almost confined to the under
parts of the body, and there is but a small tuft of white hairs behind
the ears, whereas in M. bimaculatus, the white fur extends
considerably on the sides of the body, the outer side of the limbs are
white, and there is a large and conspicuous white spot behind each ear.

In M. elegans the whole sole of the tarsus and
the
carpal
tubercles are covered with hair. In Mus bimaculatus the
hinder half of the tarsus only is covered with hair, and in M.
gracilipes both the hinder half is covered, and there are some
scattered hairs extending almost to the two tubercles, which are
situated at the base of the longer toes.

The genus Eligmodontia of M. F. Cuvier, founded
upon a
species of mouse from Buenos Ayres, possesses nearly the same
characters as the subgenus Calomys, established by me in the
Proceedings of the Zoological Society for February 1837, and which
included the animal above described, and two other species (M.
bimaculatus and M. gracilipes). M. Cuvier's genus is
distinguished by there being only one large tubercle on the under side
of the tarsus, and in having the carpal pad covered with hair as well
as the pad of the tarsus. In

these characters our present animal agrees, as it does
also in size
and in the relative proportions of the tail and tarsus, circumstances
which induce me to believe they are identical.

In M. bimaculatus and M. gracilipes there
are
six
naked tubercles on the under side of the tarsus, and the carpal pad is
also naked. In having, however, the tarsus hairy beneath,* in dentition
and in colouring, they agree so closely with M. elegans that
I
think they cannot be separated generically.

MUS BIMACULATUS.

PLATE XII.

Mus bimaculatus, Waterh., Proceedings of the
Zoological
Society of London for February 1837, p. 18.

DESCRIPTION.—Upper parts of the body of a very pale ochre
colour,
the longer hairs, however, are black, and at the apex grayish, and
where they are numerous, as on the back and upper surface of the head,
they give greater depth to the colouring; the cheeks and sides of the
body are of an almost uniform pale, but bright yellow; the sides of
the muzzle, the lower half of the cheeks, the lower portion also of the
sides of the body, and the whole of the under parts, are pure white —
each hair being uniform in colour to the root, and not, as is usually
the case, gray at the root. There is likewise a large patch
of
pure white hairs behind each ear. The feet and tail are of a pale
flesh-colour, and furnished with white hairs, with the exception of
those on the upper surface of the latter, which are pale brown. The
ears are also pale flesh-colour, clothed internally with yellow hairs;
externally on the fore part, the hairs are brownish, and on the hinder
part, white — they are rather large, and so are the feet. The tail is
about equal to the body in length. The hairs of the moustaches are
numerous and slender, and most of them are black at the base, and gray
at the apex. The hinder half of the tarsus

* In Mus leucopus of North
America the
tarsus is hairy
beneath, and in the character of the teeth this animal also agrees with
the species above mentioned.

beneath is covered with minute silvery-white hairs;
beside the
ordinary tubercles, the anterior portion of the sole of the foot and
the base of the toes beneath, are crowded with small rounded warts,
which are much more numerous and conspicuous than in the common mouse.

In.

Lines.

In.

Lines.

Length

from nose to root of tail . .

3

1

Length

from nose to base of
ear . .

0

8¾

of
tail . . . . .

1

11

of
tarsus (claws included) . .

0

8

from nose to eye . . .

0

4½

of
ear . . . . .

0

4½

Habitat, Maldonado, La Plata, (June.)

The skull of this animal, is rather shorter and broader
than that of Mus Musculus, the upper surface is more arched, the
zygomatic
arch is much more slender, and the nasal bones are rather broader. In
the convexity of the upper surface, and the slenderness of the
zygomatic arch, this skull very nearly resembles that of M.
gracilipes; this latter, however, has the zygomatic arch more
convex, projecting more suddenly on the anterior part, and the
interparietal bone smaller. Length of skull 10 lines, width 5½, length
of nasal bones 4 lines, distance between the outer side of the
incisors, of the upper jaw, and the first molar 27/8 lines. See Plate
34,
fig. 3. a.

The dentition is figured in Plate 34, figs. 3. b and c.

This mouse is rather less than M. Musculus, the
tail is
much shorter in proportion, the fur is longer and softer, and the ears
are more distinctly clothed with hair.

The pale and delicate yellow colour of the upper parts of
the body,
and the pure white of the under parts, renders the present species
conspicuous amongst its congeners. I may further remark that the white
colour which in the Muridæ (when it occurs) is usually confined to the
under part of the body, or extends but slightly on the sides, is in the
present animal extended considerably on the sides of the body, and
occupies an equal portion with the yellow of the upper parts. The name bimaculatus is applied to this animal on account of the two conspicuous white
patches, which are situated behind the ears.

In affinity as well as in appearance it most nearly
approaches to Mus
gracilipes and M. elegans; with no other species of
the
genus Mus, here described, can it be confounded, since these only have
the tarsus hairy beneath.

The principal points of distinction between the present
animal and Mus
elegans, are noticed in the account of that species.

" This mouse, when alive, had a very elegant appearance. A
countryman, who brought it me, found six of them living together in one
burrow."—D.

DESCRIPTION.—General colour very pale yellowish brown, a
tint
produced by the admixture of black and pale fawn colour; the hairs of
the ordinary fur being of the latter tint near the apex, and dusky at
the apex, whilst the longer hairs are black. The feet, tail, under
parts of the body and the sides of the muzzle, are pure white. All the
hairs of the body, (which are soft, and of moderate length), are deep
gray at the base. The ears are of moderate size, well clothed with
hairs, of which those on the inner side are yellowish, and those on the
outer, are brown on the anterior part, and white on the posterior. A
small tuft of white hairs springs from the neck immediately behind the
ears; this tuft is hidden when the ears are folded back. The tail is
slender and short, (being not quite equal to the body in length) of a
pale flesh-colour, and sparingly furnished with minute white hairs. The
feet are very small and slender, and the naked parts are of a pale
flesh-colour. The sole of the foot is covered with hairs; the toes
beneath, and the tubercles (which are as in Mus Musculus),
however,
are naked. The hairs of the moustaches are of moderate length, and of a
blackish colour, some of them, however, are grayish white.

In.

Lines.

In.

Lines.

Length

from nose to root of tail . .

2

10

Length

from nose to ear . . .

0

8¼

of
tail . . . . .

1

7

of
tarsus (claws included) . .

0

6½

from nose to eye . . .

0

41/3

of
ear . . . . .

0

4¼

Habitat, Bahia Blanca, (September.)

This species slightly exceeds the harvest mouse (Mus
messorius)
in
size, its ears are considerably larger in proportion, and the tail is
shorter. Compared with the common mouse (Mus Musculus) it is
smaller, the tail is more slender, and shorter, and the feet are
likewise more slender and proportionately much smaller; the ears are
more distinctly clothed with hairs.

The principal points of distinction between this and the
two
preceding species are pointed out in the account of M. elegans.

Upon comparing the skull of M. gracilipes (Pl.
34,
fig.
4. a.)
with that of Mus Musculus, the most striking
differences
consist in its shorter and broader form, the upper surface being more
arched, the interparietal bone has a relatively smaller
antero-posterior diameter, the occipital region is more convex, and
continued more gently and gradually into the upper region of the skull.
The zygomatic arch, which is unusually slender, is more dilated
(especially on the anterior part) thus giving a squareness to the
general form. The nasal bones are not so much attenuated posteriorly.
The length of the skull is 87/8 lines, the
greatest width is 51/8 lines,
and the distance between the outer side of the incisors and the front
molar is 2¾ lines.

The dentition is figured in Plate 34, figs. 4. b and
4. c.

" This specimen was given me by Mr. Bynoe, the surgeon of
the
Beagle, who caught it amongst some long dry grass."—D.

MUS FLAVESCENS.

PLATE XIII

Mus flavescens, Waterh., Proceedings of the
Zoological Society of London, for February 1837, p. 19.

DESCRIPTION.—Fur long and moderately soft; general colour
of the
upper parts bright brownish yellow; on the sides of the head and body
bright yellow; towards the rump of a deeper hue, and inclining to
orange; under parts pale yellow, or yellow-white; chest yellow. The
fur both of the upper and under parts of the body deep plumbeous at the
base. Feet flesh colour, covered above with white hairs: tarsi long,
naked beneath. Ears small, tolerably well clothed with hairs; those on
the inner side yellow, but many of them blackish at the base; on the
outer side, the hairs are blackish on the fore part and yellow on the
hinder part. The hairs of the ordinary fur of the back are of a deep
rich yellow colour at the tip, and the longer hairs are blackish. The
tail is long, deep brown above and whitish beneath; the hairs of the

moustaches are rather short and slender, and of a brownish
colour.
Thumb nail small and rounded.

In.

Lines.

In.

Lines.

Length

from nose to root of tail . .

3

9

Length

of tarsus . . . .

1

0½

of
tail . . . . .

4

1½

of
ear . . . . .

0

4½

from nose to ear . . .

1

0

Habitat, Maldonado, La Plata, (June.)

This species is slightly larger than the common mouse;
the head is
rather larger in proportion; the ears are rather smaller and more
distinctly clothed with hair; the tail and tarsi are much longer in
proportion. Its bright yellow colouring and proportions distinguish it
from any of the species described in this work. Of this animal I do not
possess the skull, nor of the teeth do I possess more than the first
and second molars of the upper jaw, and the second and last of the
lower jaw. These are figured in Plate 34, figs. 5. a, and 5. b.

MUS MAGELLANICUS.

PLATE XIV.

Mus Magellanicus, Bennett, Proceedings of the
Zoological Society of London for December 1835, p. 191.

DESCRIPTION.—Fur very long and moderately soft, general
colour deep
brown; the hairs of the ordinary fur are gray, tipped with yellowish
brown; the longer hairs are black; the sides of the body are
yellowish; the under parts are gray-white with a faint yellowish tint,
each hair being gray tipped with yellowish white. The ears are rather
small, well clothed with hairs; those on the inner side are blackish
tipped with yellow, and on the outer side they are blackish on the fore
part and dusky on the hinder part. The fore feet are of moderate size,
the thumb nail is short and rounded; the tarsi are rather long; both
fore and hinder feet are of a brownish colour, and covered above with
dirty gray hairs. The tail rather exceeds the head and body in length;
it is brown above and dirty white beneath. The hairs of the moustaches
are numerous and long, of a brownish colour at the apex and black at
the base.

This mouse is larger than Mus Musculus; the
tail is
rather
longer in proportion; the tarsi much longer; the ears are not quite
so large in proportion to the head, (which greatly exceeds that of Mus
Musculus in size,) and they are densely clothed with hair. The
fur
is longer. In colour, the animal here described is rather darker than
the common mouse. I have one specimen however before me which very
nearly agrees in this respect.

The dentition is figured in Plate 34, figs. 6, a. and
6, b.

From the attention which Mr. Darwin bestowed upon the
Muridæ of the
southern parts of South America, I presume his collection affords
materials for a tolerably complete monograph of the species of that
portion of the globe. The species above described, however, does not
occur in Mr. Darwin's collection, but is here introduced in order to
make the work more complete, and that I might more clearly point out
the distinctions which exist between it and other species here
described, the account given by Mr. Bennett in the Proceedings being
very short.

MUS ARENICOLA.

PLATE XIII.

Mus arenicola, Waterh., Proceedings of the
Zoological Society of London, for February 1837, p. 18.

DESCRIPTION.—Fur long, moderately soft; general colour
deep brown;
sides of the body with a very obscure yellowish hue; under parts dirty
gray with a faint yellow tint. All the fur deep gray at the base; the
hairs of the upper part of the body obscurely annulated with yellowish
brown near the apex, and dusky at the apex; the longer hairs are
black. Feet brownish, covered above with brown-white hairs; tarsi
short. Tail short, blackish above, brown-white beneath. Ears small,
well clothed with hairs; those on the

UNDER THE AUTHORITY OF THE LORDS
COMMISSIONERS OF HER
MAJESTY'S TREASURY.

ILLUSTRATIONS OF

THE ZOOLOGY OF SOUTH AFRICA :

Consisting chiefly of Figures and
Descriptions of the
Objects of Natural History collected during an Expedition
into the Interior of South Africa, in the years 1834, 1835, and 1836,
fitted out by
"The Cape of Good Hope Association for Exploring Central Africa."

TOGETHER WITH

A SUMMARY OF AFRICAN ZOOLOGY,

AND AN INQUIRY INTO THE GEOGRAPHICAL RANGES
OF
SPECIES IN THAT QUARTER OF THE GLOBE.

BY ANDREW SMITH, M.D.

SURGEON TO THE FORCES, AND DIRECTOR OF THE
EXPEDITION.

————————————————————————

Prospectus.

THE Cape of Good Hope is now acknowledged to be one of the
greatest
avenues as yet opened for the researches of the Naturalist. Our Colony
in that part of Southern Africa is the key to a large portion of an
extensive continent which is still but very partially explored; and
the field to which it admits the scientific traveller is rich to
exuberance in the variety and novelty, both of animal and vegetable
life.

Stimulated by the prospect of Discovery in a quarter so
fertile in
interest, "The Cape of Good Hope Association for Exploring
Central
Africa" was established in 1833; and in 1836, an Expedition fitted
out
by that body, consisting of thirty-four persons, and directed by Dr.
Smith, after an absence of nineteen months, and penetrating as
far as 23° 28' South latitude, returned to Cape Town laden with a
variety of curious and important specimens in Natural History, &c.

Previously to this period little information has been
furnished, in
a
shape calculated to enable the public to form accurate ideas of the
various animated beings by which these regions are inhabited. The
splendid publication of Le Vaillant, no doubt, should be mentioned as
forming an exception, pro tanto; but this includes only a
portion of
the Birds of the most southern extremity of the country, and a work
therefore extensive enough to comprehend the various departments of
Zoology is still a desideratum.

The members of The Cape of Good Hope Association for
Exploring
Central Africa found themselves, on the return of the recent
Expedition, in a situation to supply at least some portion of the
existing deficiencies; but their funds, even if it had been possible
to divert them to such an object, were altogether inadequate to defray
the expense of laying the result of their labours before the world.
Under such circumstances, it was decided that Dr. Smith, the
director of the Expedition, should be authorised, on his arrival in
England, to wait upon Lord Glenelg, for the purpose of making him
acquainted with the position and views of the Society, in the hope that
Government might be induced to assist in the publication of their
materials.

This hope has not been disappointed. At the recommendation
of the
Secretary of State for the Colonial Department, the Lords Commissioners
of Her Majesty's Treasury have been pleased, by a pecuniary grant, to
enable the
Society to publish the result of its labours, without infringing upon
the funds raised solely for the purposes of discovery; and in a form
which, while it places the work within reach of most of the friends and
promoters of science, will not, it is hoped, be found inconsistent with
the interest and importance of the subject.

The materials for the work now offered, under such
patronage, to the
public, will consist of pictorial illustrations of between three and
four hundred subjects of the animal kingdom, all of which have been
collected to the south of 23° 28' South latitude; and will comprise,

First, and principally, unknown animals;

Secondly, animals known, but not yet figured; and

Lastly, such as have been imperfectly figured; but of
which the
Association is in possession of accurate drawings.

The Entomological portion of the work will be from the pen
of W. S.
Macleay, Esq., who has kindly undertaken that department. The rest of
the descriptions will be furnished by Dr. Smith, who will add a summary
of African Zoology, and an inquiry into the Geographical ranges of
species in that quarter of the Globe.

Conditions of Publication.

The Work will appear periodically; and it is estimated
that the
whole will be completed in about thirty-four parts, price, on an
average, Ten Shillings each. As it will be necessary that the plates be
published promiscuously, they will be arranged in five divisions, viz.
MAMMALIA, AVES, PISCES, REPTILIA, and INVERTEBRATÆ. The plates of each
of these divisions will be numbered independently, and the letter-press
descriptions left unpaged, so that on the work being completed, they
may be arranged either agreeably to the general classified order which
will accompany the last number, or according to the particular views of
the purchasers.

—————————————————————

The whole of the Plates will be engraved in
the
highest style of Art, from Drawings taken expressly for this Work,
and beautifully coloured after Nature.